Episode 248: 31 fascinating facts about houseplants

Curio articulatus aka hotdog plant growing in the wild at Little Karoo in South Africa. Photograph: Gingertomcat on Shutterstock.

Subscribe to On The Ledge via Spotify, Apple Podcasts, Player FM, Stitcher, Overcast, RadioPublic and YouTube.

Become a Patron!

Support Me on Ko-fi

Transcript

Episode 248

Jane Perrone 0:15
Festive felicitations to one and all, this is On The Ledge podcast and in this week's show, we're talking facts, facts, facts - about houseplants of course. I'm your host, Jane Perrone. And in this week's show, I bring you 31 houseplant facts, one for every day of the month. Perfect to fill those awkward gaps in conversations at family gatherings this festive season.

Jane Perrone 0:50
I find myself learning loads of cool stuff about plants through the making of On The Ledge. But sometimes I come across stuff that just doesn't fit into any particular episode of the show. So in this week's On The Ledge, I am providing an information dump in the form of 31 fascinating houseplant facts that you can use in any way you wish. I'm gonna say my boring, yada yada yada thing that I say every week, but I do really mean it. Go and look at the show notes where you'll find all of these facts plus things like academic papers where I mention them, all the references are in there if you want to look at those where I've referenced academic papers.

Jane Perrone 1:36
We're not beating around the bush this week. Let's crack on with our first fact. Fact one concerns the string of pearls plant aka Curio rowleyanus. The plant formerly known as Senecio rowleyanus. And as the name suggests, this plants leaves are basically little tiny globes, I think they look more like peas than pearls. But have you ever wondered about the pointy tip at the end of each of those tiny green spheres? If you're a botanist, that's what you call a mucro.

Jane Perrone 2:28
Fact two: talking of members of the genus Curio, that genus was named by the botanist Paul V. Heath not after the word 'curio', which is usually defined as an interesting or fascinating object - often something that's either rare or strange, but after a Roman orator named Gaius Scribonius Curio, and his son of the same name.

Jane Perrone 2:58
Fact three: one other notable species in the genus Curio is curio. articulatus, commonly known as the hot dog plant, because its succulent stems look a bit like hot dogs - maybe one that's been left to go mouldy for a very long time. It does grow leaves out of those strange hotdog shapes, and has also earned the common names candle plant and pickle plant. And like so many of the succulents we love, it's native to South Africa. I've often thought that somebody with a bit of a talent for botany could have some fun by growing a hot dog plant next to a bun specifically Philodendron 'Fun Bun'. The only fly in the ointment is that Philodendron 'Fun Bun' is more of a marketing name dreamt up by nurseries, and it's correct scientific name is Thaumatophyllum spruceanum. It somewhat ruins the gag, doesn't it? You might also see this sold as Philodendron goeldii which is another scientific name it's been given, although that one's also been superseded by Thaumatophyllum spruceanum.

Jane Perrone 4:13
Fact four: talking of houseplants that look like other things. The Cactus genus Mammillaria comes from the Latin mamilla, meaning nipple, and that's referring to the little lumpy outgrowths that you find on Mammillaria species. This is what botanist would call a tubercle, which comes from the Latin word for lump hence, it's sometimes known as the nipple plant. Or, if you prefer, you can call it the pincushion cactus.

Jane Perrone 4:46
Fact five. Talking of genus names and their origins, Chlorophytum is the genus name of the spider plant Chlorophytum comosum, but chlorophytum simply translates as green plant. Ironic really given that the vast majority of spider plants grown in our homes are very good at cold fires rather than that plain green original.

Jane Perrone 5:14
Fact six, the award for the worst common houseplant name has to go to the chicken gizzard plant Iresine herbstii. The variety that is most often called chicken gizzard is Iresine herbstii 'Aureoreticulata', which has pinkish red stems and yellow and green leaves. I don't really remember what a chicken gizzard looks like. And I don't fancy googling a picture but I'm just going to assume that it looks something like the leaves. Anyway the species has these dark red leaves and that's usually called the beetroot or beefsteak plant. And not surprisingly, in its native South America this is used as a food colouring because it's just so bright red. Second prize for the worst common houseplant name goes to the plant with a scientific name myrtillocactus geometrizans cultviarfukurokuryuzinboku with the deeply awful common name boob or boobie cactus: why say boob cactus when you can say Myrtillocactus geometrizans fukurokuryuzinboku?

Jane Perrone 6:32
Fact seven: the ZZ plant aka Zamioculcas zamiifolia is the only member of the aroid family that can reproduce from fallen leaflets. This is a strategy the plant uses to save water during droughts and spread itself into clumps.

Jane Perrone 6:56
Fact eight: say Polka Dot plant and you're probably thinking about Begonia maculata. But those of us who've been on this earth a little bit longer, and we're around for the last houseplant boom may remember when Hypoestes phyllostachya was the polkadot plant. And this is a plant often recommended for terrarium, but where he grows wild in Madagascar, he grows up to a metre tall, check the show notes for a picture of it in its native habitat. And this plant has become invasive in parts of Australia.

Jane Perrone 7:36
Fact nine: do you say gesneriad [hard g] or gesneriad [soft g]? The good news is, I don't mind how you say it. And I don't think there is one right answer to that question. The name of the gesneriad family, which includes African Violets Streptocarpus and Aechynanthus (more on that later) comes from Gesneria, a genus of sub shrubs and shrubs, almost all of which are native to the islands of the Caribbean. If we were talking about animals, this will be known as the type genus, but this term doesn't have an official botanical meaning according to the International Code of Nomenclature for algae, fungi and plants. If you're wondering why you haven't seen GesneriaGesneria down your local garden centre, they're not that popular as houseplants because they are really rather hard to grow. And gesneriad was named after the Swiss naturalist Conrad Gessner or is it 'Jessner'?

Jane Perrone 8:40
Fact 10 The small orange-yellow flowers of the velvet plant Gynura auranticaca smell bad. Yes, the beautiful velvety purple foliage is something to behold. But how bad is the smell when those flowers emerge? Some describe the smell as resembling B.O., while others say they get a hint of gym sock plus a festering wound or Cheetos and feet. Researchers have been tinkering with adding growth regulators to stop the plants from flowering, but the easiest way is just to chop them off before they open. Another plant with a heinous smelling flower is the popular succulent Crassula muscoa, the watch chain succulent - cheesy feet all the way.

Jane Perrone 9:37
Fact 11: the world's smallest known bromeliad is to Tillandsia minutiflora, native to parts of Argentina, Bolivia, Paraguay and Peru. They grow in clusters but each plant is about the same size as a matchstick and magnified each plant looks like a tiny segment of a Christmas tree.

Jane Perrone 10:02
Fact 12. Talking of Christmas trees I have bought a potted Christmas tree this year rather than a cut one. I've opted for Araucaria heterophylla aka the Norfolk Island pine, named because it comes from the tiny islands off the coast of Australia called Norfolk Island. And it also occurs on Phillip Island nearby, which is even tinier than Norfolk Island pine is grown as a street tree in places like Hawaii and South Africa. And it's part of the ancient plant family of conifers named the Araucariaceae. There are supposedly golden and silver tipped varieties, but I've never seen any of these for sale in the UK, although they were available in the past and certainly caused quite a stir. Tom's Weeds, the story of Rochfords and their Houseplants by Mea Allen reports the excitement when the sport 'Silver Star', which is described as having 'fronds stiff as a ballet dancer's tutu tipped and boarded with silver, so that when you look down at it, it's seven radiating branchless look like a Silver Star'. This was shown in 1912 by the nursery, and Tom and colleagues were swept back in the excitement. And the plant was sold at a Guinea a go, which in 1912, was a lot of money. And then the book reports that this cultivar disappeared during the First World War period. I'd love to know if anyone's found one. The later generation of Rochfords became very famous in the UK in the 50s and 60s, for really establishing the houseplant trend here. Unfortunately, the nursery is lost to history, it no longer exists.

Jane Perrone 11:54
Fact 13. According to anecdotal evidence, I'm hearing from garden centres, potted Christmas trees of all kinds of proving particularly popular this year. If you do buy a potted tree, or even a cut one, one thing to watch out for is conifer aphids, and I have seen some "horror stories" in the press, about people who've found their trees are infested. These are a group of several aphid species that are kind of meaty looking, that specialise in conifers, and they can remove be removed in the same way as any other aphid sprayed off, or you can use insecticidal soap. So if you're bringing a Christmas tree in to your home, do give it a good check over before you do so.

Jane Perrone 12:43
Fact 14. Another Christmas plant. The Schlumbergera or Christmas cactus, the history of the Schlumbergeras is that make up the array of Christmas and Thanksgiving cacti is very confusing, dating back to the early 1800s When these plants started to be collected in South America. There is one easy way of classifying what kind of Schlumbergera hybrid you have, aside from noting when it flowers of course, which is not always reliable. Those hybrids that are classes the Christmas cactus, often called the Buckley group, have pink pollen, while the Thanksgiving or Truncata group have yellow pollen back to 15. Garden writer Tovah Martin reports in her book Once Upon a Windowsill that Ficus elastica aka the rubber plant caused a lot of distress to Victorian growers who loved the plant but didn't like the fact that it would weep latex, that milky sap when cut. So how did they treat it? Well, they would apply a raw hollowed out potato to the cut. I've no idea if that worked.

Jane Perrone 14:00
Fact 16. National Take your houseplant for a walk day takes place on July 27 every year, sharing the spotlight with national walk on stilts day - just don't try combining those two days in one. It's just gonna end in disaster.

Jane Perrone 14:22
Fact 17. Funnily enough, there is a houseplant that looks like it's walking on stilts. Sansevieria pinguicula is known as the walking Sansevieria, and it grows in a particular way sending out these horizontal stolons a bit like a strawberry plant or a strawberry Saxifrage and then that stolon roots into the ground above ground, so the plant looks as if it's walking on stilts after a manner at least. Check out the show notes for a paper by friend of the show Dr. Colin Walker all about this plot.

Jane Perrone 15:08
Fact 18. My wish lists plan for 2022 is Begonia chingipengii from the Philippines, and absolutely beautiful rhizomatous begonia with dark green leaves with paler veins. It's a species only described in 2014. How incredible that it's already available for us growers. This plant was named after the Taiwanese plant taxonomist Ching-I Peng, who found it while plant hunting in the Philippines. You can read the story behind Ching-I Peng's love of begonias in his book All for Love: endless trekking in search of begonia. Check the show notes for a link. Sadly, Ching-I Peng died in 2018.

Jane Perrone 15:59
Fact 19. The term caudiciform plant seems to have been around forever, but it was in fact coined by the British succulent expert Gordon Rowley, who claimed he'd exhumed it from 19th century works on gardening. Rowley defined a caudex as the axis of a plant consisting of stem and root, usually use in reference to the trunk or stem of palms and ferns. In succulents, that swollen perennial organ composed of stem or root or both, and above ground or below, from which arise slender, usually ephemeral, photosynthesizing organs and called disciform. Well, that just simply means a plant that has a caudex, I'd love to get my hands on Rowley's book called Caudiciform and Pachycaul Succulents: Pachycauls, bottle, barrel and elephant trees and their kin, a collectors miscellany published in 1987, but it's currently £300 pounds in the secondhand bookstores. So maybe that'll have to wait.

Jane Perrone 17:03
Fact 20. Back to smelly flowers. Now, geoflory is a botanical term for producing flower at ground level. And this is usually adopted by plants as a way of aiding pollination by things that are on the ground, be that mice, insects or otherwise, and they mimic the smells of things like carrying faeces and mushrooms, which of course would all be found at that level. One example of course, is Aspidistra elatior, or the cast iron plant whose flesh coloured flowers are found at ground level and are designed to attract fungus gnats. Geocarpy, on the other hand, is production of fruits underground. And the best known example is the peanut Arachis hypogaea.

Jane Perrone 17:54
Fact 21. Moon cacti those brightly coloured cacti sat atop a green stem often fail. Don't worry if this happens to you, it's really not your fault. They're only really designed to be temporary companions. Because the two plants involved aren't really that compatible. They really are the botanical equivalent of a cut and shut car. The green base is dragon fruit, one of the Hylocereus species. And the colourful top is a chlorophyll-lacking cultivar of the cactus Gymnocalycium mihanovichii. Now the Gymnocalycium need the Hylocereus because they don't have enough photosynthesizing power of their own. But as I say this is often a doomed relationship. Because the dragon fruit well that just wants to grow into a massive, sprawling epiphyte. So from a sustainability point of view, I'd say leave those Moon cacti on the shelf.

Jane Perrone 18:55
Fact 22. I mentioned Aeschynanthus earlier. Now you may have always wondered how to say this name. It's the genus name of the lipstick plant. It looks almost impossible to say it's spelled A-e-s-c-h-y-n-a-n-t-h-u-s - how on earth well just break it down. It's ess-key-NAN-thus with the emphasis on the NAN. That's my best attempt anyway. This genus has about 160 species and they all come from subtropical parts of Southeast Asia. And it's red tubular flowers are typically pollinated by sunbirds. And the name comes from two Greek words: Aischuno which means to be ashamed and anthos which means flowers. I've no idea why you'd be ashamed of red flowers, but there you go.

Jane Perrone 19:52
Fact 23 The word cachepot, French for pot cover came into the English language in the late 19th century, I found some amazing instructions for making your own bamboo cachepot using lengths of bamboo strung together on wires in a book called every man his own mechanic, which came out in 1890. And it was designed to resemble an earthenware pot that has the same kind of greeny-browny tints and presumably was designed to look like bamboo. But this is the version where you could actually make the whole thing out of bamboo. I'll put a link in the show notes if you want to try to recreate that at home.

Jane Perrone 20:34
Fact 24. Medinilla magnifica or the rose grape is one of those houseplants that many of us have tried to grow and many of us have failed with it's really not that easy to grow. This one is from the Philippines. So maybe if you live in a subtropical or tropical climate, you'd have more luck. King Boudewijn of Belgium was a big fan of the rose grape and he liked to grow them well don't think he probably crew them. He was probably his lackeys. But anyway, they were grown in his royal conservatories and featured on a banknote the 10,000 Belgian franc note featured Medinilla magnifica - I don't know if there are any other houseplants featured on banknotes around the world? Do let me know.

Jane Perrone 21:23
Fact 25. Thomas Rochford at the nursery that I mentioned in fact 12 did some incredible stands at the Chelsea flower show in the 50s and 60s, and their stand in 1969 featured a plant that you may not have come across as a houseplant, but clearly it was popular in the UK then a Cussonia spicata, an evergreen member of the Aralia family, commonly known as the cabbage tree. It comes from South Africa and has amazing leaves that look a bit like snowflakes.

Jane Perrone 21:57
Fact 26. The tiny Lord Howe Island produced not one but two hugely popular Victorian houseplants. Howea forsteriana, which is still widely grown today has a houseplant, you probably know it as the Kentia palm - and Howea belmoreana. In the trade these were known as bells and forsters. But forsteriana won out in terms of growing in homes. Although you can still find belmoreana being grown outside in places around the world. It was forsteriana that really won over the 20th century as a houseplant because it was just a little bit easier to grow her more suited to our homes and find out the full story of howeaforsteriana. In my book Legends of the Leaf out next April. Plug over.

Jane Perrone 22:52
Fact 27. Don't believe everything you read about houseplants in nursery descriptions - Geoppertia orbifolia - often still sold as Calathea orbifolia - is often described as a Bolivian plant. But if you check out Plants of the World Online, which is, in my opinion, the most reliable source of infortion, it's actually from two regions of Brazil.

Jane Perrone 23:19
Factor 28. The strawberry Saxifrage, Saxifraga stolonifera is one of my favourite houseplants and is well suited to those of us turning our heating down this winter because it likes colder temperatures indoors. One thing you may not know is that in traditional Chinese medicine Saxifraga stolonifera was used as a herbal remedy for haemorrhoids. Don't tr y it at home folks.

Jane Perrone 23:48
Fact 29. We tend to think that the whole indoor jungle thing is a new phenomenon. But in fact, looking back through history, the last 200 years at least, it's all been done before. Take clothing the walls of your rooms with climbers. Today it might be a devil's ivy EPipremnum aureum or a Philodendron hederaceum - both aroids that take centre stage, but in the Victorian age, people were clothing whole rooms with Hedera helix. Yes, that's English ivy, often doesn't do well in our homes that are centrally heated but Victorian homes it did very well in. Let me read you an extract from Vick's family magazine dated 1879. This is a letter from Mrs LSW from Minerva, Ohio. She writes "the favourite of all my houseplants is my English ivy. The branches in all measuring 85 feet and the beauty and cheerfulness it gives to our cosy little sitting room is not to be described. It extends from floor to ceiling, then almost around the sides of the room, reframing many of the pictures and the large green leaves are so pretty over the white paper. Strangers entering the room begin with, "oh!" the oh growing stronger and stronger until their eyes reached the end of the many branches. Truly a rare old plant is the ivy green and I would advise all who have none to obtain one immediately as nothing will give so much satisfaction." So there you go. That was the indoor jungle of 1879, a heck load of English ivy.

Jane Perrone 25:40
Fact 30. One species that has fallen from favour when it comes to growing as a house plant. And that's is the salak palm. And I'd never heard of this until I got hold of a book called Your Indoor Plants from Aspididtra to Zalacca by Juliana Crow. Back in 1952 The scientific name was Zalacca edulis which Juliana describes as a handsome feather palm with shining leaves and pink flowers that comes from Malaya which is of course, modern day Malaysia. Nowadays, the Latin name is Salacca zalacca - I love that - now I don't know whether this was just included because it was the only plant that began with Z back then: at the time, the Zamioculcas zamiifolia although it had been brought to the UK in the 1800s and was on display at Loddiges Nursery did not enter the houseplant trade until the 1990s. So maybe it was just included because it was the only vague houseplant beginning with Z. But it certainly is a useful and much grown tropical plant in Southeast Asia. And it's called snake palm because the fruits have this scaly skin that looks a little bit snaky. So salak palm, if anyone's growing this as a houseplant, I'd love to know.

Jane Perrone 27:14
And finally, fact 31. If you've heard a houseplant described as farinaceous but had absolutely no idea what that meant. Here's the answer. It means that the plant has got a kind of a flowery bloom on its leaves. That's known as farina or epicuticular wax. This is also known as glaucous leaves or a bloom on the leaves of houseplants. And this is really common to plants that live in high light conditions, protecting those plants from high levels of radiation from the sun. And as well as repelling water. It also helps to protect the plant from diseases and pathogens and insects that might be trying to attack them. Very important when you're living in an environment where life can be tough. And of course, farina means any powdery or mealy substance. Great examples of plants with farina, farinaceous plants or epicuticular wax if you prefer, are Kalanchoe thyrsifolia, the flapjack plant or the paddle plant with its amazing large flat leaves with this kind of powdery bloom on them. And many of these species in genera like Echeveria, and Pachyphytum also have this same covering. Bear in mind when you're touching these plants, it will leave a mark because you're removing that farina and oftentimes, that is then gone, it's not replaced. So just be careful when you're handling these plants because it can damage their appearance. So - farinaceous - see if you can slip that into a festive conversation this Christmas.

Jane Perrone 29:04
Well, that's all my facts blurted out for your entertainment. I hope you enjoyed that. And maybe you've got some fascinating houseplant facts that you'd like to share with me. I always love to hear from listeners to drop me a line to ontheledgepodcast@gmail.com. Thank you to Yael and Lorie who became Ledge Ends this week, joining the Patreon clan and I'm hearing from lots of you on Patreon that you're receiving your cards which is great news, especially those who live far away from me here in the UK. It's great to hear that listeners in America and Canada are getting their cards - if you are in Australia or New Zealand, do let me know if your card arrives because those were the ones sent out first. I know they've got further to go. So it's delightful to see you all enjoying that lovely hand lens gang design. If you go to my social media, Instagram is J.l.perrone, you can see what I'm talking about and as ever, details of Patreon are in the show notes for you to check out.

Jane Perrone 30:16
That's all for this week's show. I will be back next Friday I'm off to put up some Christmas decorations now I hope that whatever you're doing with your plants this week you take some time to look after yourself and remember that you yes you the person listening are doing great and you're worth it. I'm telling you it's true - bye!

Jane Perrone 31:09
The music you heard in this episode was Roll Jordan Roll by The Joy Drops, Nothing Like Captain Crunch by Broke For Free, and Overthrown by Josh Woodward. All Tracks are licenced under Creative Commons. Visit the show notes for details.

I often find myself learning lots of cool stuff about plants that doesn’t fit into a particular episode of the show, so in this week’s On The Ledge I’m providing an information dump - 31 fascinating houseplant facts that should provide you with plenty of conversational fodder during any awkward gaps in conversations at work parties, family gatherings or other events over the Christmas season. 

Cussonia spicata. Photograph: Leonora (Ellie) Enking on Flickr.

Hypoestes phyllostachya growing in its native Madagascar. Photograph: The Titou, Wikimedia Commons

1. The pointy tip on the spherical leaves of the string of pearls, Curio rowleyanus (formerly Senecio rowleyanus), is what botanists call a mucro.

2. Talking of members of the genus Curio - that genus was named by botanist Paul V Heath not after the word ‘curio’ but after a Roman orator named Gaius Scribonius Curio and his son of the same name.

3. One species in this genus - Curio articulatus - is commonly known as the hot dog plant (have a look at the picture at the top of the page to see if you can see the resemblace) You could make a whole ‘meal’ and grow it next to Philodendron ‘Fun Bun’ although its correct scientific name is Thaumatophyllum spruceanum, which somewhat ruins the gag. You might also see this sold as Philodendron goeldii which is another scientific name it’s been given - but that has been superseded.

4. Talking of houseplants that look like other things - the cactus genus Mammillaria is named after mamilla the Latin word for nipple: this is due to the tubercules - knobbly outgrowths - on the plant. Hence it’s sometimes called the nipple cactus but I prefer to call it the pincushion cactus.

5. Chlorophytum is the genus name of the spider plant - simply translates as ‘green plant’. Ironic, then, that the vast majority of spider plants grown in our homes are variegated cultivars rather than the plain green original. Check out my On The Ledge episode all about Chlorophytum comosum (the spider plant).

6. The award for the worst common houseplant name ever has to go to the chicken gizzard plant, Iresine herbstii. The variety that is most often called chicken gizzard is ‘Aureoreticulata’ with pinkish red stems and yellow and green leaves. The species has dark red leaves and is usually called beetroot or beefsteak plant and not surprisingly in its native south america it is used as a food colouring. Second prize goes to Myrtillocactus geometrizans cv. fukurokuryuzinboku with the deeply awful common name boob/boobie cactus.

7. The ZZ plant - Zamioculcas zamifolia - is the only member of the aroid family that can reproduce from fallen leaflets. This is a strategy the plant uses to save water during droughts.

8. Hypoestes phyllostachya - aka the polka dot plant - grows wild in Madagascar but has become invasive in parts of Australia and other places. Although it’s sometimes grown as a terrarium plant, the polka dot plant grows 1m tall in the ground.

9. How did the gesneriad family get their name? You can say gesneriad or jesneriad, I don’t mind! The name of the Gesneriad family which includes African violets, Streptocarpus and Aeschynanthus is Gesneria, a genus of subshrubs and shrubs al most all native to the islands of the Caribbean. If this were animals this would be known as a type genus but this term has no official botanical meaning according to the International Code of Nomenclature for Algae, Fungi, and Plants. Gesneria aren’t that popular as houseplants because they are really rather hard to grow. The genus Gesneria honours the swiss naturalist Conrad Gessner.

10. The small orange-yellow flowers of the velvet plant, Gynura aurantiaca, smell bad. How bad? well some describe them as resembling BO, while others say they smell like gym socks plus a festering wound, or cheetos and feet. Another plant that smells is Crassula muscosa, the watch chain succulent, which has a similarly cheesy smell. Researchers have tried adding the growth regulators to stop the plants from flowering: or, you can just cut the flowers off before they open.

11. The worlds smallest bromeliad is Tillandsia minutiflora, which is a South American plant that grows in clusters: each plant is about the same size as a matchstick. Under magnification they look like a tiny segment of a Christmas tree.

12. Rather than buying a cut tree, this year I have decided to buy a potted Norfolk Island pine (Araucaria heterophylla) as a christmas tree. It comes from two tiny Islands off the coast of Australia. As well as being popular as a houseplant around the world, the Norfolk Island pine is grown as a street tree in places like Hawaii and South Africa. It comes from the ancient plant family of conifers named Araucariaceae. There are golden and silver tipped Norfolk Island pines - or at least there were in the past. The book Tom’s Weeds tells the story of the Rochford family, who were huge figures in the British houseplant inhibited a sport called Silver Start in 1912 and sold plants for a guinea each: they nearly got swept away in the rush, according to the book.

13. Potted Christmas trees of all kinds are proving particularly popular this year, or so I am hearing from garden centres. If you buy a real tree, cut or otherwise, watch out for conifer aphids which are meaty looking aphids that specialise in Christmas tree species. They can be removed in the same way as any other aphid - sprayed with water or insecticidal soap (preferably before they come inside).

14. The history of the species in the Schlumbergera genus that make up the array of Christmas and Thanksgiving cacti is rather confusing, but there is one way to tell what kind of Schlumbergera hybrid you have - aside from noting when it flowers of course. Hybrids classed as the Christmas cactus - usually called the Buckleyi Group - has pink pollen - the thanksgiving - Truncata Group - has yellow pollen.

15. Tovah Martin reports in her book Once Upon a Windowsill that although the Victorians loved the rubber plant (Ficus elastica) they hated the way it seeped a milky latex when the plant was cut. The suggested remedy when this occurred was treating the cut with a raw hollowed out potato. I have no idea if this worked.

16. ‘National take your houseplant for a walk day’ takes place on July 27 every year, sharing the spotlight with ‘national walk on stilts day’.

17. And indeed, there is a houseplant that is known for walking on stilts - in a manner. Sansevieria pinguicula from Kenya puts out horizontal stolons that then root above ground, giving the plant a stilt-like appearance. Read more about the species in this paper by friend of the show Dr Colin Walker. You can hear Colin talking about Sansevierias more generally in On The Ledge episode 187.

18. My wishlist plant for 2022 is Begonia chingipengii from the Philippines, a new species described in 2014. It was named after the Taiwanese plant taxonomist Ching-I Peng - you can read about how he found this plant in his book All for Love: Endless Trekking in Search of Begonia. Sadly he passed away in 2018.

19. The term caudiciform plant seems to have been around forever, but it was in fact coined by the British succulent expert Gordon Rowley, who claimed he’d ‘exhumed’ it from nineteenth century works on gardening. Rowley defines a caudex as “The axis of a plant, consisting of stem and root … in succulents, that swollen, perennial organ (composed of stem or root or both, and above ground or below) from which arise slender, usually ephemeral photosynthesizing organs”. And caudiciform means simply a plant that has a caudex. I’d love to get my hands on Rowley’s book Caudiciform and Pachycaul Succulents: Pachycauls, Bottle-,Barrel-And Elephant-Trees and Their Kin a Collector's Miscellany published in 1987 but it’s currently selling for nearly £300…

20. Geoflory is a botanical term for producing flowers at ground levels - done to aid pollination which can be via mice, insects or other creatures that work at ground level. They can mimic carrion, faeces and mushrooms: a good example from the houseplant realm is Aspidistra elatior, whose flesh-coloured flowers attract fungus gnats as pollinators. Geocarpy on the other hand is production of fruits underground: the best known example is the peanut. Arachis hypogaea.

21. The reason why moon cacti - those brightly coloured cacti sat atop a green stem - often fail. That is because they are made of two rather incompatible plants that have been grafted together - the botanical equivalent of a cut-and-shut car. The green base is pitahaya aka dragon fruit (Hylocereus species) and the colourful top is a brightly coloured and chlorphyll-lacking cultivars of the cactus Gymnocalycium mihanovichii - they need the photosynthesising power of the Hylocereus, but this is often a doomed relationship as the dragon fruit wants to grow into a massive sprawling epiphyte. 

22. If you have ever wondered how to say the name of the lipstick plant, it’s easier than it looks - ess-kee-NAN-thus is my best attempt. Aeschynanthus (Gesneriaceae), a genus comprising approximately 160 species in subtropical Southeast Asia, has red, tubular flowers, typical of a sunbird pollination syndrome. The name comes from the greek aischuno (to be ashamed) and anthos (flower). I have no idea why you’d be ashamed of a red flower, but there you go. 

23. The word cachepot - French for pot cover -came into the English language in the late nineteenth century. In the book Book Every Man His Own Mechanic published in 1890 there are instructions for creating a bamboo cachepot using lengths of bamboo strung together on wires.

24. Medinilla magnifica or the rose grape is a stunning houseplant, but hard to maintain in most homes. In the tropics, it is grown as a perennial. It is also a common house plant in cooler climes. King Boudewijn of Belgium was a big devotee of Medinilla. He grew them in the royal conservatories and they were depicted on the bank note of 10,000 Belgian francs.

25. The Thomas Rochford Nursery stand at the Chelsea flower show in 1969 prominently featured a houseplant that is no longer widely available in the UK - Cussonia spicata or the cabbage tree, which is native to South Africa and has leaves like snowflakes. 

26. Lord Howe Island produced two hugely popular houseplant species in the 1800s - Howea forsteriana and Howea belmoreana: they were known in the Victorian plant trade as “bells” and “forsters”. H. forsteriana - usually known as the Kentia palm - stayed the course right through the 20th and into the 21st century, whereas belmoreana is much less commonly grown inside. This is probably because the Kentia palm suits modern homes better.

27. Geoppertia orbifolia - often still sold by its old name Calathea orbifolia - is often described in nursery blurbs as coming from Bolivia - Plants of the World Online tells us it’s actually from Brazil.

28. The strawberry saxifrage, Saxifraga stolonifera, has a long history in traditional Chinese medicine as a remedy for haemorrhoids.

29. Most houseplant trends are actually nothing new. Whereas modern growers like to clothe walls and wreathe pciture frames with devil’s ivy, Epipremnum aureum, Victorians used English ivy (Hedera helix) in the same way. Here’s a link to the article I quote from Vicks Magazine, 1879.

30. The salac palm (Salacca zalacca) may have fallen out of favour indoors, but it was once included in the title of a popular houseplant book: Your Indoor Plants from Aspidistra to Zalacca by Juliana Crow, published 1952. It’s also called the snake palm due to its scaly fruits.

31. Farinaceous means a plant that has a coating of farina - a floury bloom caused by epicuticular wax. This protects the plants from radiation from the sun, repels water and discourages insect attacks. Well known farinaceous houseplants including the flapjack plant (Kalanchoe thyrsifolia) and many species within the Echeveria and Pachyphytum. Try not to handle these plants as the farina will come off and will leave a mark.

---

---

HOW TO SUPPORT ON THE LEDGE

Contributions from On The Ledge listeners help to pay for all the things that have made the show possible over the last few years: equipment, travel expenses, editing, admin support and transcription.

Want to make a one-off donation? You can do that through my ko-fi.com page, or via Paypal.

Want to make a regular donation? Join the On The Ledge community on Patreon! Whether you can only spare a dollar or a pound, or want to make a bigger commitment, there’s something for you: see all the tiers and sign up for Patreon here.

• The Crazy Plant Person tier just gives you a warm fuzzy feeling of supporting the show you love.

• The Ledge End tier gives you access to two extra episodes a month, known as An Extra Leaf, as well as ad-free versions of the main podcast on weeks where there’s a paid advertising spot, and access to occasional patron-only Zoom sessions.

• My Superfan tier earns you a personal greeting from me in the mail including a limited edition postcard, as well as ad-free episodes.

If you like the idea of supporting On The Ledge on a regular basis but don't know what Patreon's all about, check out the FAQ here: if you still have questions, leave a comment or email me - ontheledgepodcast@gmail.com. If you're already supporting others via Patreon, just click here to set up your rewards!

If you prefer to support the show in other ways, please do go and rate and review On The Ledge on Apple Podcasts, Stitcher or wherever you listen. It's lovely to read your kind comments, and it really helps new listeners to find the show. You can also tweet or post about the show on social media - use #OnTheLedgePodcast so I’ll pick up on it!

CREDITS

This week's show featured the tracks Roll Jordan Roll by the Joy Drops, Nothing Like Captain Crunch by Broke For Free and Overthrown by Josh Woodward.